For sheer A-list, platinum-packing firepower, the sold-out “12-12-12” benefit concert for victims of Hurricane Sandy at Madison Square Garden tomorrow night may well be the biggest musical event ever staged in New York City, with a lineup that includes Bruce Springsteen and the E Street Band, the Rolling Stones, Paul McCartney, The Who, Kanye West, Eric Clapton, Bon Jovi, Alicia Keys and Billy Joel.

But beyond that, with its massive digital reach, the show is shaping up as an unprecedented worldwide event. Projected around the globe via television, radio broadcast and live Web streaming, the four-hour-plus concert has the potential to reach 2 billion people, making it the most-watched musical event ever.

To put it another way, unless you’re living in a rain forest or a monastery, when Mick Jagger wags his hips or Springsteen kick-starts the E Street Band with a wave of his Telecaster, you can probably find a way to watch it in real time.

“The difference between this event and any event that’s happened previously is the incredible evolution of digital technology,” says John Sykes, the president of Clear Channel Entertainment, who is producing the show along with Cablevision CEO James Dolan and movie mogul Harvey Weinstein.

“It’s going to be available on four or five times the number of platforms as anything shown before.”

At a press conference last weekend, the trio boasted that the concert would see unprecedented worldwide distribution, being made “available to almost anyone on the planet with a television, a radio, a smartphone, tablet, computer or Internet-connected device.”

This is good news for fans: The 13,500 tickets to the event, which ranged in price from $150 to $2,500, sold out within minutes. They quickly showed up on third-party sites, with sellers asking as much as $36,000 per ticket.

This time, pretty much every major media company in existence is getting in on the act — it’ll be live-streamed on AOL, YouTube, Hulu and Yahoo, aired on Clear Channel radio stations across the country, simulcast in movie theaters and viewable on dozens of networks and television feeds around the world, including everything from MSG, the American Forces Network and the Cooking Channel to HBO Latin America, Sundance Channel Asia and VH1 Brasil.

With this kind of multimedia firepower, the Sandy show has the potential to top even Live Aid, the 1985 concert whose global reach set the standard for superstar musical benefits, with an estimated 1.4 billion people watching.

And for the kind of music legends that will take the stage, it’s a good chance a lot of those people worldwide will be glued to their screens, says Bill Werde, the editorial director of Billboard.

“They pulled together one of the greatest lineups of all time, even in the context of these often outsized lineups for charity events,” he says. “It’s literally like everyone who’s royalty who’s left is on this bill.”

While the concert will certainly raise more than the $30 million it’s already brought in from ticket sales, the spectacle will also raise awareness, something these all-star jams excel at, Werde says. He notes that even people who were skeptical about the Live8 concert that addressed poverty in 2005 had to admit it brought the issue to light.

“The whole world stopped and talked about this issue for a few days, or a week, or whatever,” he says. “That’s really meaningful. They’re going to raise a lot of money for a lot of people who were affected by Sandy.”

The seed for the big event was planted just days after the storm, says Sykes, when he, Weinstein and Dolan spoke on the phone about the possibility of repeating their post-9/11 effort with another concert. As the days passed and “we really saw the magnitude of the disaster and the long-term impact, we decided to greenlight it,” he says.

The next step, he says, was “teaming up and going after people we know to bring them under the tent.”

The first two artists approached were Bruce Springsteen and Paul McCartney, who both signed on immediately. And from there the roster started filling quickly, in part due to the musicians’ efforts: Eddie Vedder signed on after getting a call from Roger Waters, while McCartney reached out to Dave Grohl of the Foo Fighters.

“It really grew virally. Before we knew it we had just about every great legend in rock,” says Sykes, who notes that many of the performers have ties to the area, while others “made their names here.” He deems the final result “probably the greatest lineup that’s ever performed on one stage.”

Of course the point of all this is not to count boldface names, but to raise money. While he won’t put out a target figure, Sykes says they hope to surpass the $56 million the Concert for New York City ultimately raised after 9/11 by “millions and millions.”

And when it comes to fund-raising, the operation is again making a full-court digital press, via texts, Web donations and other platforms that weren’t even conceived of a decade ago. Still, he says, old-fashioned methods still play a key role.

“When it comes to getting dollars in fast,” Sykes says, “the telephone is still the driving force.”